Main Uses

This testing machine is used to determine the compressive strength of bricks, stones, concrete, and other building materials.
This machine features electric hydraulic loading, sensor force measurement, computer operation, and strength calculation. It complies with the national standard "Standard Test Methods for Mechanical Properties of Ordinary Concrete." The automatic loading speed and loading method are program-controlled, making the measurement results more accurate. It also has functions such as loading speed control, peak value hold, and overload protection. It is an essential testing and inspection device for construction, building materials, highways, bridges, and other engineering units.
This testing machine and its accessories comply with the requirements of standards GB/T2611, GB/T17671, GB/T16826, and GB/T50081.

Main Technical Parameters

1. Maximum load range: 2000KN
2. Grade: Level 1
3. Minimum resolution: 0.1KN
4. Maximum distance between pressure plates: Manual screw 320mm
5. Upper/lower pressure plate dimensions: φ250mm, 260×350mm
6. Piston diameter × maximum stroke: φ250mm × 80mm
7. Motor power: 1.1KW
8. Power supply: AC380V ±10V / 50Hz
9. Overall dimensions: 960 × 490 × 1270mm
10. Total weight: 750Kg

Structure Overview

The testing machine mainly consists of three parts: the machine body, hydraulic control box, and servo control system.

1. Machine Body Part

The machine body connects the cylinder and upper beam with four columns. On the upper beam of the testing machine, there is an adjusting screw mechanism (handwheel, screw, nut) that can adjust the no-load height of the machine. The lower end of the screw is equipped with a ball seat and upper pressure plate. The lower pressure plate is placed on the piston of the oil cylinder. When the specimen contacts the upper pressure plate, the ball seat of the upper pressure plate can self-adjust to balance, keeping the specimen and upper pressure plate level. The lower pressure plate has positioning marks for the specimen. During testing, the specimen should align with these marks. Below the lower pressure plate is a dust cover to prevent or reduce dust from entering the cylinder during piston movement, which could damage the cylinder or oil seal. There is a sealing device between the piston and cylinder to prevent oil leakage, but a small amount of oil leakage may still occur during use. At the top of the cylinder, there is an annular oil groove and an oil discharge channel that returns oil to the main oil tank.

2. Hydraulic Control Part

The control box of this testing machine mainly consists of an oil tank, oil pump, motor, servo valve, and return valve. During loading, the microcomputer controls the loading speed to regulate the piston’s rising speed (the servo valve and safety valve are integrated). After the test ends, the oil cylinder slowly descends. The safety valve is preset to an appropriate position at the factory, and users should not adjust it during normal use.

Installation of the Testing Machine

1. When hoisting the testing machine, pass the lifting wire rope through the lifting ring screw at the top of the screw.
2. Install the testing machine on a stable foundation about 20 cm above the ground. Two M10 anchor bolts should be embedded; see foundation drawings for dimensions.
3. When installing the testing machine, use a 1/1000 frame level to measure the flatness of the lower pressure plate to ensure it is level. If not level, adjust with shims (shim plates placed under the nut of the column).

Maintenance and Care

1. Install the testing machine in a clean, dry, temperature-uniform environment free from vibration and corrosive gases.
2. Keep the testing machine clean. Parts on the surface without protective coating should be regularly oiled to prevent rust.
3. Use 46# anti-wear hydraulic oil.
4. Initial operation and trial run: After installation, before the first start, check whether the motor rotation direction matches the oil pump rotation direction. If not, adjust the motor rotation direction.
After connecting the main oil cylinder pipe, air may enter and needs to be removed. To remove air: start the oil pump, close the return valve, let the oil rise the piston a short distance, then open the return valve to let oil flow back to the oil tank. Repeat several times to purge air before starting formal testing. Air removal is only required during the first startup, unless oil is changed or necessary.

Calibration of the Testing Machine

1. This testing machine should be calibrated once a year.
2. Calibration should be performed under the following conditions:
(1) Room temperature within 20±10℃.
(2) Relative humidity ≤ 80%.
(3) In a vibration-free environment.
(4) Power supply voltage fluctuation within ±10% of rated voltage, with relatively stable voltage.
3. After powering on the instrument, preheat for 30 minutes and zero it according to the usage method.
4. Start the motor and repeat loading to the maximum load three times, then set the load display to zero and begin calibration.